Interactions between a Barotropic Vortex and an Idealized Subtropical Ridge. Part I: Vortex Motion

Abstract

A series of barotropic modeling experiments are used to examine the motion of a vortex in the vicinity of an idealized subtropical ridge. The vortex propagation is highly correlated with the absolute vorticity gradient in the initial imposed environment. The signal is degraded when radial band averages are used to calculate the environmental advection and absolute vorticity gradient components. It is shown here that this is due partially to the difficulties in separating the cyclone from its environment. Application of the modeling results to climatological mean fields indicates that considerable variations in vortex propagation can occur.